A & P - digestive system Flashcards
(215 cards)
1
Q
what are the functions of the digestive system?
A
to provide energy
to build new tissue
2
Q
what is the structure of the digestive system?
A
a long muscular tube from mouth to anus with modifications in various regions
3
Q
what are the accessory organs of the digestive system?
A
salivary glands, liver and pancreas
4
Q
what is the central upper abdominal region called?
A
epigastrium
5
Q
what is the central lower abdominal region called?
A
hypogastrium or suprapubic
6
Q
what is the peritoneum?
A
a double layer of serous membrane which covers the abdominal and pelvic cavities
7
Q
what is the position of the parietal peritoneum?
A
it lines the body wall
8
Q
what is the position of visceral peritoneum?
A
it covers the organs
9
Q
What is the position of the peritoneal cavity?
A
it lies between the parietal and visceral peritoneum, it contains only serous fluid
10
Q
The intraperitoneal organs are fully covered by the peritoneum, which organs are these?
A
stomach
part of small intestines
11
Q
The retropertineal organs are partially covered by peritoneum, what are the organs and which position are they in?
A
pancreas and part of duodenum
pushed against posterior abdominal wall
12
Q
What is the mesentery?
A
double layer of visceral peritoneum which attaches organs to body
13
Q
What is the Omentum?
A
double layer of visceral peritoneum which attaches one organ to another
14
Q
Name the 4 basic layers of the gastrointestinal tract
A
mucosa
submucosa
muscularis externa
serosa or adventia
15
Q
where is the mucosa found in the GI tract?
A
forms lining of tract
16
Q
name the 3 layers of the mucosa
A
epithelium
lamina propria
muscularis mucosa
17
Q
what is the function of the epithelium of the mucosa in the GI tract?
A
protective
secretive
absorptive
18
Q
what is the structure of the lamina propria of the mucosa in the GI tract?
A
connective tissue containing vessels, glands and lymphoid tissue
19
Q
what is the structure of the muscularis mucosa of the mucosa of the GI tract?
A
smooth muscle
inner-circular
outer-longitudinal
20
Q
what is the structure of the submucosa?
A
dense irregular connective tissue
21
Q
what is the function of the submucosa?
A
supports mucosa
provides vascular, lymphatic and nerve (submucosal plexus) supply
22
Q
what is the structure of the muscularis externa?
A
smooth muscle
inner- circular
outer - longitudinal
23
Q
what is the function of the muscularis externa?
A
GI movements (peristalsis and segmentation)
24
Q
what lies between the circular and longitudinal layers of smooth muscle in the muscularis externa?
A
myenteric plexus
25
what is the serous?
serous membrane that covers structures in the peritoneal cavity
26
name the 3 branches of the abdominal aorta that supply the GI tract
celiac trunk
superior mesenteric artery
inferior mesenteric artery
27
which system allows the blood from the stomach, pancreas, small and large intestine drain into the liver/
hepatic portal system
28
what is the function of the liver?
processes nutrients and secretes bile
29
what is the action of the autonomic nervous system on the GI tract?
causes long reflexes- large scale peristalsis etc.
30
which nerves control autonomic nervous system responses to the GI tract?
Vagus and Glossopharyngeal
31
where are most postganglionic nerves located?
enteric nervous system (submucosal and myenteric plexuses)
32
what action does the enteric nervous system have on the GI tract?
short reflexes - local peristalsis and glandular secretions
33
which glands control digestive function?
endocrine glands
34
what are the functional processes of the digestive system?
```
motility
digestion
secretion
absorption
protection
```
35
name 3 types of mechanical digestion
chewing
churning
segmentation
36
name 4 types of propulsion
swallowing
peristalsis
mass movement
elimination of waste
37
why does food need to be broken down by mechanical digestion?
move easily along tract
| increase surface area to aid chemical digestion
38
what is the function of the temporomandibular joint and muscles?
aids the action of the teeth
39
what is the function of the salivery glands?
to produce saliva which begins chemical digestion and moistens bolus
40
what is segmentation?
cycles of contraction which fragment bolus and mix with digestive juices
41
what is peristalsis?
waves of muscle contraction which move bolus along
42
what are mass movements?
powerful peristalsis contractions
43
what stimulates the defecation reflex?
faeces in rectum
44
which sphincter needs conscious effort to relax?
external sphincter
45
what is chemical digestion?
breakdown of food into small fragments allowing absorption
46
what are carbohydrates broken down into during chemical digestion?
simple sugars
47
what are proteins broken down into during chemical digestion?
amino acids
48
what are lipids broken down into during chemical digestion?
fatty acids and monoglycerides
49
where are carbohydrates broken down?
mouth
| small intestine
50
where are proteins broken down?
stomach
| small intestine
51
where are lipids broken down?
mouth
| small intestine
52
name some secretions secreted into the GI tract
water, enzymes, hormones
53
name 2 exocrine glands of the GI tract
salivary glands
| pancreas
54
what do endocrine glands secrete?
hormones
55
what is absorption in the GI tract?
passage of substances across digestive epithelium to blood or lymph
56
Where does absorption occur in the GI tract?
stomach
small intestine
large intestine
57
what does the GI tract protect itself against?
acids
mechanical trauma
bacteria
58
what is the action of salivary amylase?
starts digestion of carbohydrates in the mouth
59
what is the action of lingual lipase?
starts digestion of lipids in the mouth
60
how much saliva is produced per day?
1 - 1.5 litres
61
the salivary glands produce serous fluid, what is its function?
wash oral cavity
62
what produces mucin?
the salivary glands, for lubrication
63
why do the salivary glands produce lysozyme?
it has antibacterial properties
64
how long is the oesophagus?
25cm long
65
where do the oesophagus go from and to?
pharynx to stomach
66
what is the oesophagus lined with?
stratified squamous epithelium
67
describe the different muscle types of the oesophagus
upper third - skeletal
middle third - mixed
lower third - smooth
68
Which nervous system innervates the oesophagus?
autonomic nervous system
69
which region of the abdomen is the stomach located?
epigastrium
70
what are the functions of the stomach?
```
storage
mechanical/chemical digestion
protection (kills microorganisms)
absorption (alcohol/ aspirin)
production of intrinsic factors
```
71
Describe the structure of the muscles of the stomach - inner, middle and outer
inner - oblique
middle - circular
outer - longitudinal
72
what is the function of rugae in the stomach?
increase surface area
73
what is the function of the mucous cell and neck mucous cell in the gastric pit?
secrete mucus
74
what is the function of the parietal cell in the gastric gland?
secrete hydrochloric acid and intrinsic factors
75
what do the chief cells in the gastric gland secrete?
pepsinogen
76
what do the enteroendocrine cells in the gastric gland secrete?
gastrin
77
how much gastric juice is produced daily?
1.5 - 2 litres
78
what activates the secretion of gastric juice?
low pH
gastrin
histamine
ACh
79
what is the function of hydrochloric acid in the stomach?
kill microbes
breakdown connective tissue (meat) and cell walls (plant)
activates pepsinogen to covert to pepsin
80
what is the function of pepsin?
starts protein digestion
81
what does gastrin stimulate?
secretion of pepsinogen and HCL
| contraction of gastric wall
82
what is the function of intrinsic factors in gastric juice?
aids vitamin B12 absorption
83
what initiates the cephalic phase of gastric activity?
sight, smell, taste of food
84
what initiates the gastric phase of gastric activity?
food in stomach
85
what stimulates gastric juice production in the gastric phase?
gastrin
86
what initiates the intestinal phase of gastric activity?
partially digested food in duodenum - slows down gastric juice production and motility
87
describe the position of the pancreas
retroperitoneal
| sits in curve of duodenum- posterior to stomach
88
name 3 parts of pancreas
head, tail ,body
89
name the sphincter where the pancreatic duct opens into the duodenum
sphincter of Oddi
90
how much pancreatic juice is secreted daily?
1.5 litres
91
what do the acini cells secrete?
enzymes
92
name the types of enzymes the acini cells produce
propeptides - digest protein
amylase - digests carbhydrates
lipase - digests fats
ribonuclease and deoxyribonulease - digest RNA and DNA
93
name the 3 propeptides enzymes that the acini cells secrete
trysinogen
chymotrysinogen
procarboxypeptidase
94
where are acini cells found
pancreas
95
what do duct cells in the pancreas secrete?
water
| sodium bicarbonate
96
name the endocrine cells of the pancreas
Islets of Langerhans
97
what do the Islets of Langerhans produce?
alpha cells - glucagon
| beta cells - insulin
98
describe the position of the liver in the abdominal cavity
right hypochodrium and epigastrium
99
what is the weight of the liver?
1.5 kg
100
name the 4 lobes of the liver
right
left
caudate
quadate
101
what is the function of the liver in relation to the digestive system?
bile production
102
what are the dimensions of the gall bladder?
8cm long by 4cm wide
103
what is the function of the gall bladder?
stores and concentrates bile
104
how much bile can the gall bladder hold?
40-70ml
105
what adaption does the gall bladder have which helps it to expand?
rugae
106
how long is the small intestine?
6 metres
107
mane the 3 modifications that the small intestine uses to increase surface area?
pilcae circulares
villi
microvilli (brush border)
108
what are the functions of the small intestines?
absorption
mechanical digestion
chemical digestion
109
what leads to the secretion of CCK (cholecystokinin) in duodenum?
presence of fat and proteins
110
describe the actions of CCK in chemical digestion
pancreatic acini cells - enzymes released
gall bladder - bile released
sphincter of Oddi - relaxes
stomach - reduced gastric motility and secretions
111
describe the actions of secretin in chemical digestion
pancreatic ducts - water and sodium bicarbonate released
liver- bile secreted
Stomach - reduced gastric motility and secreation
112
what reduces gastric motility and secretions in the stomach during chemical digestion?
CCK and Secretin
113
what converts trysinogen to trypsin during protein digestion?
enterokinase (located on brush border in duodenum)
114
what does trypsin activate?
other propeptides
115
what does the propeptide Chymotrysinogen convert to?
trypsinogen
116
what does the propeptide Procarboxypeptide convert to?
carboxypeptidase
117
what breaks down proteins into amino acids?
activated peptidases (such as trypsinogen)
118
what breaks down carbohydrates?
pancreatic amylase
119
what does pancreatic amylase break carbohydrates into?
disaccharides
| trisaccharides
120
what coverts disaccharides and trisaccharides into monosaccharides?
brush border enzymes
121
what coverts maltose?
maltase
122
what coverts lactose?
lactase
123
what converts sucrose?
surase
124
how emulsifies large lipid droplets to small?
bile
125
what does pancreatic lipase break triglycerides down into during fat digestion?
free fatty acids
| glycerol
126
what is formed when free fatty acids and glycerol interact with bile salts?
micelles
127
how do micelles enter intestinal cells?
diffusion
128
what are chylomicrons?
triglycerides formed from the re-synthesis of free fatty acids and glycerol
129
how are chylomicrons secreted into interstitial fluid?
exocytosis and diffusion into lacteals
130
describe the dimensions of the large intestine
1.5m long x 7.5cm diameter
131
name 2 functions of the large intestine
absorption of water and electrolytes
| storage of undigested materials
132
what is the taenia coli of the large intestine?
longitudinal smooth muscle that forms haustra
133
what are the haustra of the large intestine?
small pouches caused by sacculation
134
what are epiploic appendages of the large intestine?
small pouches of fat
135
what are the crypts of the large intestine?
glands in lining
136
what are goblet cells?
cells which produce lots of mucus
137
what is the function of bacterial flora in the large intestine?
ferment undigested carbohydrate
| synthesis vitamins B & K
138
what is the daily amount (of fluid and food) ingested and secreted into the body?
9200ml
139
what is the daily amount (of fluid and food)absorbed into the blood?
9050ml
140
what is the total amount (of fluid and food) which we excrete daily?
150ml
141
what are essential nutrients?
nutrients which can only be found in diet
142
what are macronutrients?
water, carbs, protein, fats - needed in large amounts
143
what are micronutrients?
vitamins and minerals - small amounts needed
144
why do we need nutrients?
growth and repair
145
name 3 types of carbohydrate
monosaccharides, disaccharides, polysaccharides
146
name 3 monosaccharides
glucose, galactose, fructose
147
name 3 disaccharides
sucrose, lactose, maltose
148
name 3 polysaccharides
starch, glycogen, cellulose - complex carbs
149
what do all carbohydrates generate?
glucose
150
name 3 functions of carbohydrates
convert to energy
provide energy stores
form structural components of other molecules eg. glycoprotiens
151
In what form are carbohydrates stored?
glycogen
152
what is fibre?
animal or plant carbohydrate that can't be digested
153
what are the functions of fibre?
absorb water from intestines, soften stools
| provide bulk - increase transit time
154
what is our daily requirement of fibre?
24g
155
what is our daily requirement of carbohydrate?
230g
156
what are the functions of proteins?
```
formation of: skeletal muscle
hormones
enzymes
cell membrane receptors
collagen
haemoglobin
```
157
what is protein broken down to?
amino acids
158
what do proteins synthesis?
new proteins - transamination in liver
159
how many amino acids are there?
20
160
how many amino acids can't be synthesised by body?
8
161
give some examples of amino acids
```
leucine
phenylalanine
glutamine
lysine
tyrosine
methionine
```
162
what is our daily requirement of protein?
45-60g
163
which protein source plant or animal contains complete proteins and all essential amino acids
animal
164
what % of the body is made up of lipids?
men 15%
| women 25%
165
what is the daily requirement of lipids?
70g/ only 20g should be saturated
166
what are lipids the precursor of?
steroids
bile salts
vit D
prostaglandins
167
Are lipids higher or lower in energy than sugars?
2 x higher
168
name 2 uses of lipids
absorption of fat-soluble vitamins
| plasma membrane and myelin production
169
how are lipids transported in the blood?
as lipoproteins
170
what are lipids the core of?
cholesterol and triglycerides
171
what are lipids the outer coating of?
proteins and phosolipids
172
name 3 types of lipoproteins
high-density (HDLs)
low-density (LDLs)
very low-density (VLDLs)
173
what is the function of chylomicrons?
to transport triglycerides and cholesterol from small intestine to liver
174
what is the function of VLDLs?
transport triglycerides and cholesterol from liver to adipocytes
175
what is the function of LDLs?
transport cholesterol to tissue
176
what is the function of HDLs
empty shells made in liver which collect cholesterol dn return to liver for excretion - these are the best forms of lipoprotein
177
name 4 vitamins which the body can store
A, D, E, K - they are fat soluble so are stored in fat
178
name 2 vitamins which the body can't store
B and C - they are water soluble so can't be stored
179
recommended sodium intake?
6g per day but only need 2g
180
name some examples of minerals
calcium, phosphorus, iron, magnesium, manganese, chlorine, folate
181
name 5 minerals required during pregnancy
calcium. folate, zinc, iron, iodine
182
how many servings of carbohydrate is needed daily?
6-11
183
what is metabolism?
chemical and physical reactions that occur in body to ensure growth and functioning
184
what is anabolism?
Building up - small molecules join to form complex structures (uses energy)
185
what is catabolism?
breaking down - large molecules to small ones (releases energy)
186
how many kilojoules is in 1 kilocalorie?
4.184
187
what is a kilocalorie?
heat required to heat 1 litre of water by 1 degree (c)
188
what is metabolic rate?
rate of energy released from cells
189
what is basal metabolic rate?
energy release required to support vital organs at rest
190
during carbohydrate anabolism what is glucose converted to?
glycogen or triglycerides for storage
191
during carbohydrate catabolism what is glucose used to form?
ATP by glycolysis or the TCA cycle
192
Does glycolysis require oxygen?
No
193
what happens to glucose during glycolysis?
it splits into 2 pyruvic acid - producing 2 ATP
194
what happens to pyruvate if there is no oxygen present?
lactic acid is formed - result only 2 ATP
195
what happens to pyruvate if there is oxygen present?
pyruvate passes to mitochorion where it is converted to acetyl co enzyme A, it then enters TCA cycle and electron transport chain producing 36 ATP.
add this to 2 ATP formed in glycolysis and total of 38 ATP are formed for 1 glucose molecule
196
what are formed during protein anabolism?
new proteins made from amino acids
197
what are formed during lipid anabolism?
fatty acids and glycerol
| triglycerides during lipogensis from amino acids anf glucose
198
name the 2 metabolic states
absorptive
| post -absorptive
199
what is the purpose of the absorptive metabolic state?
mainly anabolic processes build up stores of energy
200
what is the purpose of the post absorptive metabolic state?
mainly catabolic process with breaks down stores for energy
201
why is blood glucose homeostasis important?
maintains blood glucose levels
202
what is the normal range of blood glucose?
3. 5-8 mmol/L
| 3. 5-5.5 mmol/L fasting
203
what is glycogenesis?
creation of glycogen from glucose
204
what is glycogenolysis?
breakdown of glycogen into glucose
205
what is gluconeogenesis?
creation of new glucose from amino acids
206
is blood glucose high or low during absorptive state?
high
207
what does insulin do? and where is it secreted?
lower blood glucose - produced in the beta cells of pancreas
208
how does insulin lower blood glucose? (4)
increases entry of glucose into cells
stimulates glycogenesis
stimulates protein and fat synthesis
inhibits gluconeogenesis
209
how is blood glucose level maintained?
secretion of glucagon, adrenaline and glucocorticoids
210
where is glucagon secreted from?
alpha cells in pancreas
211
what does glucagon stimulate
glycogenolysis, gluconeogenesis and lipolysis
212
when are ketones produced?
when liver breaks down fats and proteins
213
how are ketones produced?
too much acetyl CoA to enter TCA cycle so acetyl CoA converts to ketone bodies
214
which cells need ketone bodies
heart and kidneys
215
what is ketoacidosis
too many ketones
